Previous research showed that scoliosis patients do not have impaired postural balance when compared to healthy controls, while several others did find an effect of scoliosis on postural balance. This discrepancy in findings may be due to differences in curve characteristics included and their effects on postural balance, curve types (single or double), number of different curve types, location of curves (thoracic and lumbar), and/or Cobb angles. Furthermore, Schimmel et al. found that postural balance one year after surgery did not improve as a result of the better spinal alignment, neither did the reduced range of trunk motion inherent to fusion negatively affect postural balance.